As a method for producing zinc cyanurate, which is known as a corrosion inhibiting coating agent for an iron-based metal surface, a disclosure is made of a method which comprises reacting zinc oxide and cyanuric acid in boiling water (see Patent Document 1). Also disclosed is a technology for producing basic zinc cyanurate particles by exerting a shearing action on a paste by means of a pin disc mill or a blade mill while heating the paste at 50 to 250° C., the paste being formed by mixing zinc oxide and cyanuric acid in a proportion of 10 to 80% by weight (based on the paste) such that they form a kneadable paste at as low a water content as possible (see Patent Document 2).